The invention relates to a heating device for fuel, in particular diesel oil, comprising a housing with an inlet and an outlet for the fuel, at least one metal plate which is disposed inside said housing, and on which tablets made of a material with a positive temperature coefficient (PTC) are fastened in a way which conducts heat and electricity, and means for the supply of electric power.
Such a device is known from U.S. Pat. No. 4,501,255.
Paraffin constituents and the like in diesel oil have a tendency to solidify again when cold, which can cause the fuel filter to become blocked. This disadvantage can be prevented by using the above-mentioned device.
In the known device the metal plate is provided on two sides with partitions which define flow paths. This principle exhibits the problem that, due to the low flow velocity of the fuel through the flow paths, the flow will be essentially laminar. The heat transfer is therefore not optimum. The low coefficient of heat transfer means that, in order to obtain a satisfactory result, the dimensions of the heating device have to be relatively large.